A continuously variable ratio transmission unit having a housing (116) and input (102, 106) and output (100) discs paired to define first and second toroidal cavities. The discs (100, 102, 106) are mounted to the housing for rotation about a common axis. first (110) and second (112) rollers—or more typically first and second sets of rollers—are respectively arranged in the first and second cavities and serve to transmit drive between the input and output discs. first (130) and second (148, 150, 152) actuators act on the respective rollers. The first actuator is coupled to a first carrier part (126) which can be mated with the housing introducing it to the housing along a direction generally parallel to the variator axis. The second actuator is coupled to a second carrier part (146) which can be mated with the housing by introducing the second carrier part to the housing along a direction non-parallel to the variator axis.
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10. A method of constructing a continuously variable ratio transmission unit (“variator”) comprising a housing, a first input/output disc pair defining a first variator cavity, a second input/output disc pair defining a second variator cavity, the discs being mounted to the housing for rotation about a common variator axis, at least one first roller disposed in the first variator cavity and at least one second roller disposed in the second variator cavity, a first actuator for applying a biasing force to the first roller and a second actuator for applying an adjustable biasing force to the second roller, the method comprising constructing the first actuator on a first carrier part and advancing the first carrier part in a direction along the variator axis to thereby mate the first carrier part to the housing, constructing the second actuator on a second carrier and advancing the second carrier part along a direction non-parallel to the variator axis to thereby mate the second carrier part to the housing.
1. A continuously variable ratio transmission unit (“variator”) comprising a housing, a first input/output disc pair defining a first variator cavity, a second input/output disc pair defining a second variator cavity, the discs being mounted to the housing for rotation about a common variator axis, at least one first roller disposed in the first variator cavity and at least one second roller disposed in the second variator cavity, the rollers serving in use to transmit drive between the input and output discs, a first actuator for applying a biasing force to the first roller and a second actuator for applying an adjustable biasing force to the second roller, wherein the first actuator is coupled to a first carrier part, the housing and the first carrier part being formed such that the first carrier part can be mated with the housing by introducing the first carrier part to the housing along a direction substantially parallel to the variator axis, and the second actuator is coupled to a second carrier part, the housing and the second carrier part being formed such that the second carrier part can be mated with the housing by introducing the second carrier part to the housing along a direction non-parallel to the variator axis.
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This is a National Phase of International Application No. PCT/GB2003/003948, filed on Sep. 11, 2003, which claims priority from Great Britain Patent Application No. 0224646.0, filed on Oct. 23, 2002.
The present invention relates to a continuously variable ratio transmission unit (“variator”) and to a method of assembly thereof.
The general construction of variators of toroidal-race, rolling-traction type will be familiar to the skilled person. Typically two toroidal cavities are defined between facing surfaces of a set of variator discs all of which are mounted for rotation about a common axis. Drive is transmitted between the discs by a set of rollers in both of the cavities and the inclination of the rollers with respect to the discs is able to change in accordance with changes in variator drive ratio. A biasing force, along a direction transverse to the disc axis, is applied to each roller by an actuator which in existing designs is of hydraulic type.
Fabrication and in particular assembly of existing variators is somewhat complex. The discs, actuators and rollers are typically all mounted in a housing and assembling the various parts inside the housing is in current prototypes a somewhat time consuming process not easy to automate or adapt to production line techniques.
A first object of the present invention is to provide a variator which is capable of straightforward assembly.
The need to provide for hydraulic fluid supply to the several actuators has meant some complication in the machining of the variator's components, particularly the housing. The applicant has previously proposed, in order to simplify construction, to form passages for the fluid supply between confronting faces of a multi-part casing—see its published International Patent Application PCT/GB99/02968. Nonetheless an additional or alternative object of certain embodiments of the present invention is to provide, in a variator, a means of fluid supply to the hydraulic actuators which is straightforward in fabrication and assembly.
The shape of the variator housing is in many cases a crucial design issue. The current need is for variators which can be installed in existing motor vehicle designs. Hence in rear wheel drive cars the variator is to be installed in the transmission tunnel. Both excessive length and width of the variator could be problematic, and in particular laterally projecting “lobes” needed in existing designs to accommodate the roller control actuators, create installation difficulties. An additional or alternative object of the present invention is to provide a variator whose external shape is suited to installation in a motor vehicle.
In accordance with a first aspect of the present invention there is a continuously variable ratio transmission unit (“variator”) comprising a housing, a first input/output disc pair defining a first variator cavity, a second input/output disc pair defining a second variator cavity, the discs being mounted to the housing for rotation about a common variator axis, at least one first roller disposed in the first variator cavity and at least one second roller disposed in the second variator cavity, the rollers serving in use to transmit drive between the input and output discs, a first actuator for applying a biasing force to the first roller and a second actuator for applying an adjustable biasing force to the second roller, wherein the first actuator is coupled to a first carrier, the housing and the first carrier being formed such that the first carrier can be mated with the housing by advancing the first carrier in a direction along the variator axis, and the second actuator is coupled to a second carrier, the housing and the second carrier being formed such that the second carrier can be mated with the housing by advancing the second carrier along a direction non-parallel to the variator axis.
In accordance with a second aspect of the present invention there is a method of constructing a continuously variable ratio transmission unit (“variator”) comprising a housing, a first input/output disc pair defining a first variator cavity, a second input/output disc pair defining a second variator cavity, the discs being mounted to the housing for rotation about a common variator axis, at least one first roller disposed in the first variator cavity and at least one second roller disposed in the second variator cavity, a first actuator for applying a biasing force to the first roller and a second actuator for applying an adjustable biasing force to the second roller, the method comprising constructing the first actuator on a first carrier and advancing the first carrier in a direction along the variator axis to thereby mate the first carrier to the housing, constructing the second actuator on a second carrier and advancing the second carrier along a direction non-parallel to the variator axis to thereby mate the second carrier to the housing.
In accordance with a third aspect of the present invention there is a continuously variable ratio transmission unit (“variator”) comprising a variator housing, a first input/output disc pair defining a first variator cavity, a second input/output disc pair defining a second variator cavity, the discs being mounted to the housing for rotation about a common axis, three first rollers disposed in the first variator cavity and three second rollers disposed in the second cavity, the rollers serving in use to transmit drive between the input and output discs, each of the first rollers being operably coupled to a respective first actuator and each of the second rollers being operably coupled to a respective second actuator, the actuators each serving to apply to their associated rollers an adjustable biasing force and each being mounted to the variator housing, the second actuators all being arranged to one side of a plane containing the variator axis and the first actuators being angularly spaced about the axis and thus disposed to either side of the said plane.
Specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:
The general construction of a toroidal-race, rolling traction type variator will firstly be described with reference to
The illustrated variator is of the type known in the art as “torque control”. The hydraulic actuator 32 exerts a controlled force on the roller/carriage and for equilibrium this must be balanced by the reaction force upon the roller resulting from the torques transmitted between the disc surfaces 18, 20, 22, 24 and the roller 28. The axis determined by the actuator 32 is angled to the plane perpendicular to the variator axis. This angle is referred to as the “castor angle”. The well known result of this arrangement is that in use each roller automatically moves and precesses to the location and tilt angle required to transmit a reaction torque determined by the biasing force from the actuator 32. Reaction torque, in this context, means the sum of the torques input to and output from the variator. The force from the actuator 32 is controlled by means of a hydraulic circuit through which fluid is supplied to the actuators at a variable pressure.
The present invention is however, applicable to variators of so-called “ratio control” type in which roller position is sensed and adjusted to provide a chosen ratio.
In
The rollers, discs and shaft are all contained within a housing 116. In the present embodiment the housing is a cast and machined metal structure. The shape of the housing is well, suited to incorporation into the tunnel of a conventional rear wheel drive motor car, its end 118 which lies toward the car's engine in use being relatively wide but leading via a tapering, frusto-conical transition region 120 to a narrower section 122. This housing shape creates potential difficulties in assembly of the variator but such problems are avoided in the illustrated embodiment by breaking down some major variator components into a set of sub-assemblies, as will now be explained.
A first sub-assembly 123 is illustrated separately from the housing and other variator components in
A second sub-assembly of the variator comprises a second carrier part formed as a carrier block 146. The carrier block 146 carries the actuator housings 148, 150, 152 associated with the three second rollers 112. Housing 152 is in the background and is largely hidden in
Two of the actuator housings 148, 150 are juxtaposed in this arrangement but are separated along the direction of the variator axis. The orientations of the second actuator housings 148, 150, 152 result in the rollers being equally angularly spaced about the variator axis even though their actuators are not.
To receive the first carrier part 124, the variator housing 116 has an axially facing recess 154 (see
The arrangement of the actuator housings not only allows for convenient assembly but also enables them to be arranged in the bell-mouthed housing 116 in a space-saving manner. At the wider region of the housing 116, the first actuator housings 130 associated with the first toroidal cavity are at regular angular intervals about the variator axis making good use of the extra width and height available here. At the narrower region of housing the placement of the second actuator housings 148, 150, 152 allows them to be fitted into the available space.
The illustrated arrangement provides for fluid supply to the roller control actuators in a constructionally convenient manner. In
A back plate 164 covers the rear face of the plate 126 and confines fluid in the channels 158, 160. Of course the channels could be machined in the back plate rather than, or as well as, the plate 126 if desired.
The second carrier part 146 can also form a manifold, by virtue of channels formed within the part 146 or in its surface, for distribution of hydraulic fluid.
Looking now at
The actuator is double-acting, having opposed working chambers 714, 716 on opposite sides of the piston 704. It is necessary to maintain a seal where the piston rod 706 emerges from the cylinder despite the lateral movement of the piston rod in this region resulting from its swashing motion and this is achieved by a floating seal arrangement 714 received in an annular recess 716 and capable of limited lateral movement The seal arrangement comprises a ring 718 formed in this embodiment of plastics and carrying an “L” section sealing band 720 biased radially inwardly by a first pre-stressed resilient loop 722 to form a seal against the piston rod 706 and also biased along an axial direction by a second pre-stressed resilient loop 724. Lateral movement of the piston rod 706 displaces the seal arrangement 714 in its recess 716 but does not impair the seal provided.
Ports 726, 728 are provided in the casting forming the actuator housing for fluid supply to the chambers 714, 716.
Patent | Priority | Assignee | Title |
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10253875, | Dec 16 2009 | Allison Transmission, Inc. | System and method for multiplexing gear engagement control and providing fault protection in a toroidal traction drive automatic transmission |
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8578802, | Dec 16 2009 | Allison Transmission, Inc. | System and method for multiplexing gear engagement control and providing fault protection in a toroidal traction drive automatic transmission |
8721494, | Dec 15 2010 | Allison Transmission, Inc | Variator multiplex valve scheme for a torroidal traction drive transmision |
8727942, | Dec 15 2010 | Allison Transmission, Inc | Dual pump regulator system for a motor vehicle transmission |
8744697, | Dec 16 2009 | Allison Transmission, Inc. | Variator lockout valve system |
8770018, | Dec 16 2009 | Allison Transmission, Inc. | Variator fault detection system |
8821340, | Dec 16 2009 | ABB Technology Ltd | System and method for controlling endload force of a variator |
8840522, | Dec 15 2010 | Allison Transmission, Inc | Variator switching valve scheme for a torroidal traction drive transmision |
8852049, | Dec 16 2009 | Allison Transmission, Inc. | Fast valve actuation system for an automatic transmission |
9103434, | Dec 16 2009 | Allison Transmission, Inc. | Fail-to-neutral system and method for a toroidal traction drive automatic transmission |
9228650, | Aug 16 2010 | Allison Transmission, Inc. | Gear scheme for infinitely variable transmission |
9267582, | Dec 16 2009 | Allison Transmission, Inc. | System and method for multiplexing gear engagement control and providing fault protection in a toroidal traction drive automatic transmission |
9347555, | Dec 16 2009 | Allison Transmission, Inc. | Variator lockout valve system |
9534672, | Dec 15 2010 | Allison Transmission, Inc. | Variator switching valve scheme for a torroidal traction drive transmission |
9541191, | Dec 15 2010 | Allison Transmission, Inc. | Dual pump regulator system for a motor vehicle transmission |
9562594, | Dec 15 2010 | Allison Transmission, Inc. | Variator multiplex valve scheme for a torroidal traction drive transmission |
9784366, | Dec 16 2009 | Allison Transmission, Inc. | Fast valve actuation system for an automatic transmission |
Patent | Priority | Assignee | Title |
5316526, | Jul 13 1990 | Torotrak (Development) Limited | Transmission of the toroidal-race rolling-traction type |
DE19961692, | |||
EP1350987, | |||
GB1500763, | |||
JP8135746, | |||
WO15978, | |||
WO9934133, |
Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
Sep 11 2003 | Torotrak (Development) Limited | (assignment on the face of the patent) | / | |||
May 31 2005 | DUTSON, BRIAN JOSEPH | TOROTRAK DEVELOPMENT LIMITED | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 017678 | /0499 | |
Mar 27 2018 | TOROTRAK DEVELOPMENT LIMITED | Allison Transmission, Inc | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 046112 | /0801 |
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